(1) Field of the Invention
This invention relates to a facsimile apparatus for transmitting an image data read from a document to an addressee through lines.
(2) Description of the Related Art
Facsimile transmission is done by connecting lines of an addresser and an addressee and sending an image data read from a document from the addresser to the addressee.
The lines are connected by dialing a line number of the addressee. In some recent models, however, line numbers can be registered in advance to eliminate the step of dialing or the same image data can be transmitted to multiple addressees one after another. There are other functions of selecting a vertical resolution or the like of the image data in accordance with the purpose, of reducing the size of the image data in accordance with the size difference between the document of the addresser and the recording paper of the addressee, and of compressing the image data with various compressing modes for sending or receiving the data in order to improve transmission efficiency.
A known facsimile apparatus, however, has the following problems. Concerning selection of vertical resolution selection or the like, since a non-standard one should be selected for each transmission by the user, operability cannot remarkably be improved even if the apparatus is equipped with the function of registering line numbers. Compressing mode selection is conducted in accordance with the conditions, functions and the like of the two apparatus. Therefore, exchange of such information and data compression based on the selected compressing mode are done after the lines are connected. Since this prolongs transmission time, the telephone fee is raised and also the apparatus cannot be used for receiving or the like during the prolonged transmission time. These problems are especially conspicuous for serial multiple addressing.
In order to solve these problems, Japanese Patent Publication Kokai No. 60-64572 has disclosed a construction wherein image data read by a reading section is first compressed with the MR (Modified READ), MH (Modified Huffman) or other data compressing mode and then stored in a memory, whereby the compressing mode is compared with a compressing mode of the addressee with which the compressed data is restored into its original form (will be referred to as addressee compressing mode hereinafter), for the purpose of multiple addressing. If the two of them correspond to each other, the image data is directly transmitted from the memory. However, if the two of them do not correspond, the stored image data is output to an expanding device for restoring it to its original form and is compressed again with the same compressing mode as the addressee compressing mode before transmission. This does not solve the problem of prolonged transmission time, or worse, further prolongs it.